Oxygen toyere of a steel-melting mill

ABSTRACT

The present invention relates to an oxygen tuyere of a steelmelting mill, whose body has pipes for supplying oxygen, a cooling medium and a shielding gas, coaxially arranged therein. The lower portion of the body of the tuyere has nozzles for supplying oxygen into liquid metal and slot-like nozzles for supplying a shielding gas, disposed above the former ones and forming a spiral, at least, a double-turn one, which embraces the body along its periphery.

United States Patent Chaikin et al.

[54] OXYGEN TOYERE OF A STEEL- MELTING MILL [72] Inventors: BorisSemenovich Chaikin, Moscow; Lev Ivanovich Kozlov, Khimki Moskovskooblasti; Thomas Vasilievich Malchenko; Konstantin Dmitrievich Mokrushin,both of Cherepovets Vologodskoi; Lev Volfovich Yarovsky, Moscow; GrigoryEfimovich Maryanchik, Moscow;

Boris Stepanovich Zhelnov, Moscow; Vasily Mikhailovich Tarasov, Moscow;Kirill Mikhailovich Trubetskov, Moscow; Igor KonstantinovichBorschevsky, Moscow; Dmitry Pavlovich Chermensky, Vidnoe Moskovskoioblasti, all of U.S.S.R.

[73] Assignee: Gosudarstvenny Sojuzny Institut PoProektirovanijuagregatov Staleliteinogo I Prokatnogo Proizvodstva DlyaChernoi Metallurgii,

Moscow, U.S.S.R.

[22] Filed: Feb. 2, 1971 [21] Appl. No.: 111,926

[ 1 Oct. 10,1972

[52] US. Cl. ..266/34 L, 75/60 [51] Int. Cl. ..C2lc 7/00 [58] Field ofSearch ..75/59, 60; 266/34 L, 34 LM,

[56] References Cited UNITED STATES PATENTS 2,829,960 4/1958 Vogt..75/60 3,045,997 7/1962 Hudson ..266/34 L 3,488,044 1/1970 Sheperd..266/34 L Primary ExaminerGerald A. Dost Attorney-Waters, Roditi,Schwartz& Nissen [57] ABSTRACT The present invention relates to anoxygen tuyere of a steel-melting mill, whose body has pipes forsupplying oxygen, a cooling medium and a shielding gas, coaxiallyarranged therein. The lower portion of the body of the tuyere hasnozzles for supplying oxygen into liquid metal and slot-like nozzles forsupplying a shielding gas, disposed above the former ones and forming aspiral, at least, a double-turn one, which embraces the body along itsperiphery.

1 Claim, 2 Drawing Figures OXYGEN TOYERE OF A STEEL-MELTING MILL Theinvention relates to the field of production of steel by way of blowingoxygen through liquid metal in a steel-melting mill, e.g., a furnace ora converter, and, more particularly, to an oxygen tuyere installed insaid mill.

An oxygen tuyere of a steel-melting mill, whose body has pipes forsupplying oxygen, a cooling medium and a shielding gas, coaxiallyarranged therein, is known. The lower portion of this body has nozzlesfor supplying oxygen into liquid metal, communicated with a duct, alongwhich oxygen is delivered, and nozzles for supplying a shielding gas,arranged above the former nozzles and communicated with the interpipespace along which a shielding gas is delivered. The latter nozzles aremade cylindrical, are equidistantly spaced from one another and arearranged along an imaginary circumference along the periphery of thebody of the tuyere (cf. British Pat. No. 934,1 12;Cl. 51(] )b, I962).

The nozzles supplying a shielding gas create a gas shield intended todecrease the amount of iron oxides (brown smoke) carried away from theworking space of the metallurgical unit, and, therefore, to raise theoutput of ready metal; to prevent drops of metal and slag from gettingonto the ceiling and walls of the steel furnace, and, therefore, topreclude premature damage of the furnace; and to provide for a morecomplete combustion of carbon oxide separated in the course of theblowing-through, and, consequently, to raise the temperature of the slagand to decrease its foam-formation, which improves the transfer of heatto the metal and prevents the latter from being carried away with theslag being removed.

In the known tuyere, however, this gas shield has a plurality of portswhose number depends on the distance between adjacent nozzles. Throughthese ports" of the shield carbon oxide penetrates and is carried awayfrom the working space, and drops of the metal and slag get onto theceiling and walls of the steel furnace.

In the known tuyere the nozzles cannot be brought closer to one anotheras it is necessary to provide a jacket of the cooling medium aroundevery nozzle, since otherwise the tuyere will burn out.

This contradiction leads to the fact that in the conventional tuyere ofa steel-melting mill there is no continuous screen from the shieldinggas, which results in all negative consequences following therefrom, andthe tuyere proper has a low resistance due to its poor cooling in thezone of disposition of the nozzles for supplying the shielding gas.

Thus, the problem lies in decreasing the number of the ports in the gasshield and, at the same time, in taking measures aimed at preventing theworsening of the conditions of the tuyere cooling in the zone ofdisposition of the nozzles supplying the shielding gas.

An object of the present invention is to provide such an oxygen tuyereof a steel-melting mill, that would create a continuous shielding screenabove the liquid metal in the steel-melting mill.

Another object of the present invention is to provide such an oxygentuyere that would be sufficiently cooled in the zone of disposition ofthe nozzles supplying a shielding gas.

The afore-said and other objects are accomplished by that the nozzlesfor supplying a shielding gas are made as slots forming a spiral, atleast a double-turn one, which embraces the body of the tuyere along itsperiphery.

The following description of an exemplary embodi ment of the presentinvention is given with reference to the accompanying drawings, inwhich:

FIG. 1 shows a longitudinal section of an oxygen tuyere of asteel-melting mill, built according to the present invention;

FIG, 2 is a section taken along line ll-Il of FIG. 1.

An oxygen tuyere comprises a body 1 (FIGS. 1,2) having pipes 2,3,4 and 5coaxially arranged therein. Oxygen is supplied into an annular duct 6between the pipes 2 and 3 along a pipe branch 7, and is blown throughnozzles 8 into liquid metal (not shown in the drawing).

A shielding gas (air) is delivered along an annular duct 9 between thepipes 4 and 5 through a pipe branch 10, and is supplied into a furnace(not shown in the drawing) through nozzles arranged in the body abovethe nozzles 8 and made as slots 11 forming a doubletum spiral embracingthe body 1 along the periphery thereof. The slots 11 are disposed withrespect to the surface of the liquid metal at an angle of 45 so that, onleaving the slots, the shielding air forms a continuous shielding screenabove the zone of the oxygen blowingthrough.

To cool the tuyere, a cooling medium (for example, water) is deliveredthrough a pipe branch 12 into an annular clearance 13 between the pipes3 and 4 and then the pipes 3 and 5, which water is then drained from thetuyere along ducts 14 and the pipe 2, as well as along a duct 15 betweenthe pipe 5 and the body 1, and is then converged in an outlet pipebranch 16.

The above-described design of the nozzles for supplying a shielding airmakes it possible to obtain a continuous shielding screen and provides,at the same time, for a reliable cooling of the body 1 at the point ofdisposition of the slots 11 for supplying a shielding air.- Thecontinuous shield is created due to the fact that the slots 11 embracethe whole perimeter of the tuyere, the reliability of the cooling-beingprovided due to the fact that the slots are made as a double-turnhelical line. At the same time, due to the great pitch of the spiral,there is provided a sufficiently great cross-sectional area for passageof the water.

To preclude the destruction of the tuyere by the stresses arising in thebody 1 during its heating, the tuyere is equipped with two stuffing boxdevices 17 and 18.

The movement of the water in the tuyere is shown by solid arrows, themovement of the shielding air-by dotted arrows, and the movement ofoxygen by dashed-dotted arrows.

We claim:

1. An oxygen tuyere of a steel-melting mill, comprising a body havingpipes for supplying oxygen, a cooling medium and a shielding gas,coaxially arranged therein; nozzles for supplying oxygen into liquidmetal, disposed in the lower portion of said body and communicated witha duct along which oxygen is delivered; nozzles for supplying saidshielding gas, disposed in said body above said nozzles for supplyingsaid oxygen, made as slots forming a spiral, at least a double-turn one,which embraces said body along its periphery, and communicated with aninter-pipe space along which said shielding gas is supplied.

1. An oxygen tuyere of a steel-melting mill, comprising a body havingpipes for supplying oxygen, a cooling medium and a shielding gas,coaxially arranged therein; nozzles for supplying oxygen into liquidmetal, disposed in the lower portion of said body and communicated witha duct along which oxygen is delivered; nozzles for supplying saidshielding gas, disposed in said body above said nozzles for supplyingsaid oxygen, made as slots forming a spiral, at least a double-turn one,which embraces said body along its periphery, and communicated with aninter-pipe space along which said shielding gas is supplied.